1) Field of the Invention
The present invention relates to a plural liquid pack-type heat curable polyisocyanate-glycidyl acrylate compound resinous composition, and a process for producing a shaped resin article therefrom. More particularly, the present invention relates to a plural liquid pack type heat curable polyisocyanate-glycidyl acrylate compound resinous composition having a low viscosity, curable at a relatively low temperature having an excellent storage stability, handling property and moldability, and useful for producing a shaped resin article having a superior heat resistance, chemical resistance, and mechanical strength, and a process for producing a shaped resin article therefrom with a high reproducibility and stability.
2) Description of the Related Art
Due to recent technological developments, various new types of resinous materials having an excellent heat resistance, mechanical properties, and moldability are now in demand.
Among these new resinous materials, the most noticeable is a reaction-molding type resin comprising a reactive monomer or oligomer. This reaction-molding type resinous material refers to a heat-curable resinous material having a relatively low viscosity, preferably being in the state of a liquid at room temperature, and capable of being simultaneously molded and cured (hardened or polymerized).
The heat curable resinous materials include polyurethane resins, epoxy resins, unsaturated polyester resins, polyvinylester resins and polydicyclopentadiene reins. Some of the above-mentioned resinous materials already have been commercially produced and marketed.
Nevertheless, these conventional heat-curable resinous materials are advantageous from the standpoint of some properties thereof, but disadvantageous from the viewpoint of other properties thereof. For example, the conventional polyurethane resins usually have a low heat resistance and the conventional unsaturated polyester resins and epoxy resins are too hard and fragile, and exhibit an unsatisfactory reactivity, although they have a higher heat resistance than that of the conventional polyurethane resins.
British Patent No. 1,104,394 discloses an improvement in the heat resistance of the conventional polyurethane resins, obtained by introducing an isocyanurate ring structure derived from a trimerization of an isocyanate compound thereinto. This improvement has long been known and practiced in the polyurethane resin industry, but is effective only for increasing a heat-distortion temperature of a heat-cured polyurethane resin by about 20.degree. C. to 30.degree. C., and thus the resultant heat-cured polyurethane resin exhibits a heat-distortion temperature of not higher than about 150.degree. C. to about 160.degree. C. Also, the viscosity of this type of polyurethane resin is not always satisfactorily low.
A well known heat-curable resin produced by using, as a component, a polyisocyanate compound, is a heat curable resin having an oxazolidone ring structure derived from a reaction of an isocyanate group in a polyisocyanate compound with an epoxy group in an epoxy compound.
As a recent development, Japanese Unexamined Patent Publication No. 62-6879 disclosed a heat curable resin having the isocyanurate ring structure derived from a trimerization of an isocyanate compound together with the above-mentioned oxazolidone ring structure.
This heat curable resin is advantageous in having an enhanced heat resistance, but is disadvantageous in that the viscosity and reaction temperature of the resin are not satisfactorily low, and the handling property and moldability of the resin are unsatisfactory due to the use of the epoxy compound.
Also, Japanese Examined Patent Publication No. 53-31,515 discloses a process for producing a polymerizable resin by reacting a polyisocyanate compound with an acrylic acid ester compound or .alpha.-alkylacrylic acid ester compound having an epoxy group. In this process, in a first step, the isocyanate groups of the polyisocyanate compound are reacted with the epoxy group of the acrylic or .alpha.-alkylacrylic ester compound, to provide a polymerizable resin having an oxazolidone ring structure, and in a second step, to the resultant reaction mixture is added a radical curing catalyst, to cause a polymerization of the remaining vinyl groups of the acrylic or .alpha.-alkylacrylic acid ester compound. Therefore, the resultant heat curable resin exhibits a high viscosity, and thus is not suitable for a reaction molding process.
Further, Japanese Examined Patent Publication No. 53-31515 does not give a general description of a proportion in amount of the polyisocyanate compound to the acrylic or .alpha.-alkylacrylic acid ester compound having an epoxy group, but merely discloses, in an example thereof, that the isocyanate group and the epoxy group are present in a proportion in an equivalent of 1:1.